1. Field of the Invention
The present invention relates to the art of protective coatings for high temperature environments and methods of applying the protective coatings, particularly to an interior surface of a domestic oven.
2. Discussion of the Prior Art
It is widely known to form domestic ovens from metal and to coat the interior metallic surfaces of the domestic ovens with compositions to protect against corrosion, high temperature effects and the like. The compositions are often chosen based on their ease of cleaning. However, the choice of compositions has been severely limited, mainly because these compositions must be stable at elevated temperatures. Because many domestic ovens today include self-clean cycles, which use temperatures typically over 700° F. (370° C.), the coatings must be resistant to temperatures well above the self-clean cycle temperatures. In general, such coatings have been essentially limited to ceramic/porcelain materials.
Ceramic coatings are known to be expensive and can be difficult to apply to substrate, i.e., the application of ceramic materials to the interior surfaces of domestic ovens can be problematic. For example, one method of applying ceramic coatings to substrate is the electrostatic application of wet porcelain suspensions. In this method, an electrostatic charge is applied to droplets of the porcelain suspension. A cloud of the charged droplets is then sprayed on the substrate. The charges on the droplets are immediately dissipated when they strike the substrate. Therefore, only the Theological character of the porcelain suspension causes the droplets to remain in place on the substrate. This makes it difficult to move the substrate without disturbing the porcelain suspension. Another method of applying ceramic coatings is the application of dry ceramic powders. This method also has problems, including the difficulty of shifting the substrate so that the powder does not partially or entirely flake and fall free from the substrate. Since chipped or fractured areas are more prone to corrosion, avoiding this problem is necessary. Based on the above, the application of ceramic coatings is complicated and not extremely economic.
Due to the problems with ceramic coatings and the lack of alternatives that can withstand extreme temperatures, as well as other necessary functional characteristics, there exists a need for a novel, thermally stable coating composition and an effective method of applying such a composition to substrates such as domestic ovens.